Simplify futility move count array formula

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 1317fc239ddc46c22f89167b2516f645ed33aa13..a16fceb1351f3a9bda4f7c8619f2201ae9d301ad 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -126,6 +126,7 @@ void Search::init() {
   {
       double    pvRed = 0.00 + log(double(hd)) * log(double(mc)) / 3.00;
       double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
+
       Reductions[1][1][hd][mc] = int8_t(   pvRed >= 1.0 ?    pvRed + 0.5: 0);
       Reductions[0][1][hd][mc] = int8_t(nonPVRed >= 1.0 ? nonPVRed + 0.5: 0);
 
@@ -139,8 +140,8 @@ void Search::init() {
   // Init futility move count array
   for (d = 0; d < 32; ++d)
   {
-      FutilityMoveCounts[0][d] = int(2.4 + 0.222 * pow(d * 2 + 0.00, 1.8));
-      FutilityMoveCounts[1][d] = int(3.0 + 0.300 * pow(d * 2 + 0.98, 1.8));
+      FutilityMoveCounts[0][d] = int(2.4 + 0.773 * pow(d + 0.00, 1.8));
+      FutilityMoveCounts[1][d] = int(2.9 + 1.045 * pow(d + 0.49, 1.8));
   }
 }
 
@@ -787,6 +788,9 @@ moves_loop: // When in check and at SpNode search starts from here
           }
       }
 
+      // Speculative prefetch as early as possible
+      prefetch((char*)TT.first_entry(pos.key_after(move)));
+
       // Check for legality just before making the move
       if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
       {
@@ -1136,6 +1140,9 @@ moves_loop: // When in check and at SpNode search starts from here
           &&  pos.see_sign(move) < VALUE_ZERO)
           continue;
 
+      // Speculative prefetch as early as possible
+      prefetch((char*)TT.first_entry(pos.key_after(move)));
+
       // Check for legality just before making the move
       if (!pos.legal(move, ci.pinned))
           continue;